Different . Different kinds of cancer have different signs and symptoms based on what kind of cancer it is, how aggressive it is, where it is located, what organ systems are affected and the age of the patient. So unfortunately, there are no specific tests or lists of symptoms that can be used to screen for cancers in general.
The good news is that childhood cancers are very rare - only 14 in 100, 000 kids will get cancer - and that childhood cancers in general are very curable (70%).
Sometimes, a doctor might spot the early signs of cancer at a check-up, but this is not usually the case. The signs and symptoms are usually very non-specific and can be attributed by the doctor and the parents to very common illnesses. As doctors, we rely on parents to let us know when they have specific concerns about a child's health since parents know the child best. A few signs to bring up to your child's doctor are:
- continuing, unexplained weight loss
- development of excessive bruising, bleeding or rash
- unexplained fever lasting more than a week
- persistent headaches with nausea and vomiting in the morning
- noticeable tiredness and paleness
- swelling of persistent pain in bones, joints, back or legs
- a mass or lump - especially in the abdomen, neck, armpits, groin, or chest
- a white spot in the pupil of the eye or sudden vision changes that persist
- constant infections (though keep in mind that a healthy child can have more than 10 colds a winter)
don't panic if you've noticed one of these symptoms in your child - none of the above symptoms always equal cancer. Many of those symptoms are caused by much more common, less scary diseases. However, these symptoms usually deserve a work-up to find a cause regardless of what it may be, so it's definitely worth bringing it up to your child's doctor if you've noticed any of the above. And the list above is far from complete, so if you have any specific concerns about your child, be sure to discuss them with your child's doctor.
Legal disclaimer: I am providing this general and basic information as a public service and my response to this question does not constitute a doctor-patient relationship. For any additional information, advice, or specific concerns, please speak with your own physician. The information provided is current as of the date of the answer entry.